We could say the same about the Homeric epics. One does not end up producing the canonical version of an oral tradition by blindly recording whatever lyrics are

We could say the same about the Homeric epics. One does not end up producing the canonical version of an oral tradition by blindly recording whatever lyrics are circulating at the time. A great poet(s?) rearranges, reinterprets, and infuses the story with a unique perspective that can be identified as his (or theirs), even thousands of years later.